c.1227_1228dupGG (p.Glu410Glyfs), a frequent variant in Tunisian patients with MUTYH associated polyposis.

INTRODUCTION: Familial adenomatous polyposis (FAP) is an autosomal dominant-inherited disease caused by germline variants in the APC gene. It is characterized by the development of hundreds to thousands of adenomatous polyps in colon and rectum. Recently, biallelic germline variants in the base excision repair (BER) gene: MUTYH have been identified in patients with attenuated FAP and/or negative APC result. It can be responsible for an autosomal recessive inherited colorectal cancer syndrome (MAP syndrome: MUTYH-associated polyposis). OBJECTIVE: The aim of this study was to evaluate germline variants of MUTYH gene in Tunisian patients with attenuated FAP. METHODS: thirteen unrelated patients from Tunisia with attenuated FAP were screened for MUTYH germline variants. Direct sequencing was performed to identify point variants in this gene. RESULTS: A Biallelic MUTYH germline variant were found in all patients and showed an attenuated polyposis phenotype almost of them without extra-colic manifestations: The known pathogenic frameshift variant c.1227_1228dupGG (p. Glu410Glyfs) was found, in homozygous state, in 13 index patients. CONCLUSION: Patients with attenuated familial adenomatous polyposis (<=100) and no obvious vertical transmission of the disease should be considered for MUTYH gene testing.

Squamous cell carcinoma of the rectum cured after chemoradiation.

The primary squamous cell carcinoma of the rectum is a rare tumor that presents epidemiological, etiopathogenic and evolutionary characteristics different from those of adenocarcinoma . We report the case of a primary squamous cell  carcinoma well  differentiated  from medium-high   rectal junction in a 59 year old patient treated with a chemoradiation first ,followed by surgical resection. However, the anatomical examination of the  surgical specimen did not show tumoral tissue.